package euler.p051_100;

import java.math.BigInteger;

import euler.MainEuler;
import euler.helper.NaturalHelper;

public class Euler055 extends MainEuler {
    /*
        If we take 47, reverse and add,
        47 + 74 = 121,
        which is palindromic.

        Not all numbers produce palindromes so quickly.
        For example,

        349 + 943 = 1292,
        1292 + 2921 = 4213
        4213 + 3124 = 7337

        That is, 349 took three iterations to arrive at a palindrome.

        Although no one has proved it yet, it is thought that some
        numbers, like 196, never produce a palindrome.
        A number that never forms a palindrome through the reverse
        and add process is called a Lychrel number.
        Due to the theoretical nature of these numbers, and for the
        purpose of this problem, we shall assume that a number is
        Lychrel until proven otherwise.
        In addition you are given that for every number below ten-thousand,
        it will either
            (i) become a palindrome in less than fifty iterations, or,
            (ii) no one, with all the computing power that exists, has managed
                so far to map it to a palindrome.

        In fact, 10677 is the first number to be shown to require over
        fifty iterations before producing a palindrome:
        4668731596684224866951378664 (53 iterations, 28-digits).

        Surprisingly, there are palindromic numbers that are themselves
        Lychrel numbers; the first example is 4994.

        How many Lychrel numbers are there below ten-thousand?
     */
    public String resolve() {

        int count = 0;
        int limite = 10000;

        for (int i= 0; i < limite; i++) {
            boolean isLychrel = true;

            BigInteger n = BigInteger.valueOf(i);
            n = n.add(NaturalHelper.reverso(n,10));

            for (int j = 0; isLychrel && j < 50; j++) {
                if (NaturalHelper.isPalindromo(n)) {
                    isLychrel = false;
                } else {
                    n = n.add(NaturalHelper.reverso(n,10));
                }
            }

            if (isLychrel) {
                count++;
            }
        }

        return String.valueOf(count);
        // 249
    }

}
